Power on time delay circuit

This circuit is time delay circuit to power on.Most of electrical equipments burn due to power failures so this circuit is a best answer for that.

5 To 30 Minute Timer Circuit

This is so useful circuit because by using this circuit you can operate some thing with the delay of 5 min to 30 min.don't use NE555 here because the value of transistors it will not work here.





Parts


IC1: 7555

B1: 9V

C1: 33uF CAP

Q1: BC109C NPN

D1: 1N4004 DIODE

C2: 100n CAP

Relay 9 volt coil with c/o contact

S1: On/Off

S2: Start

S3: Range

R6,R5,R4,R3,R2,R1: 8.2M RESISTOR

R8: 100k RESISTOR

R7: 4.7k RESISTOR

9 second Visual Timer Circuit

This is very useful circuit for you,Because you all can use this timer for various purposes.And the impotent thing of this circuit is giving a visual signal through LEDs.This is 9 second timer.This operates with 12v power.So you can use this one as a timer for your vehicle.

0 to 20 seconds timer

Most of people asked about a short time timer.So I decided to introduce you this one.Here The time is adjustable from 0 to about 20 seconds.you can chang the time of it by changing the C1 Capacitor.So try this..







Parts:

R1 1 Meg Pot

R2 10 K 1/4 Watt Resistor

D1,D2 1N914 Diodes

C1 10uf 16V Electrolytic Capacitor

C2 0.01uf Ceramic Disc Capacitor

U1 555 Timer IC

RELAY 9V Relay

S1 Normally Open Push Button Switch

Note

# Use R1 to chang the time of Timer
# By changing the C1 capacitor You can change the time of timer

Long duration timer circuit.

This is a long duration timer you can operate this up to 35 min.so you can use this one for your tv or to your electrical equipment.so enjoy this..

Long duration timer circuit.

This timer circuit can be used to switch OFF a particular device after around 35 minutes. The circuit can be used to switch OFF devices like radio, TV, fan, pump etc after a preset time of 35 minutes. Such a circuit can surely save a lot of power.







The circuit is based on quad 2 input CMOS IC 4011 (U1).The resistor R1 and capacitor C1 produces the required long time delay. When pushbutton switch S2 is pressed, capacitor C1 discharges and input of the four NAND gates are pulled to zero. The four shorted outputs of U1 go high and activate the transistor Q1 to drive the relay. The appliance connected via the relay is switched ON. When S2 is released the C1 starts charging and when the voltage at its positive pin becomes equal to ½ the supply voltage the outputs of U1 becomes zero and the transistor is switched OFF. This makes the relay deactivated and the appliance connected via the relay is turned OFF. The timer can be made to stop when required by pressing switch S1.



Notes.

* Assemble the circuit on a good quality PCB or common board.
* The circuit can be powered from a 9V PP3 battery or 12V DC power supply.
* The time delay can be varied by varying the values of C1&R1.
* The push button switch S2 is for starting the timer and S1 for stopping the time.
* The appliance can be connected via contacts N1 & N2 of the relay RL1.
* The IC U1 is 2 input quad NAND gate 4011.

Digital Stop Watch

A digital stop watch built around timer IC LM555 and 4-digit counter IC MM74C926 with multiplexed 7-segment LED display.MM74C926 consists of a 4-digit counter, an internal output latch, npn output sourcing drivers for common cathode,






7-segment display and an internal multiplexing circuitry with four multiplexing outputs.The counter advances on negative edge of the clock. The clock is generated by timer IC LM555.The circuit works off a 5V power supply. It can be easily assembled on a general-purpose PCB. Enclose the circuit in a metal box
with provisions for four 7-segment displays, rotary switch S1, start/stop switch S2 and reset switch S3




Testing

First, reset the circuit by pressing S3 so that the display shows ‘0000.’ Now open switch S2 for the stop watch to start counting the time. If you want to stop the clock, close S2. Rotary switch S1 is used to select the different time periods at the output of the astable multivibrator (IC1).

Long duration timer circuit.

This timer circuit can be used to switch OFF a particular device after around 35 minutes. The circuit can be used to switch OFF devices like radio, TV, fan, pump etc after a preset time of 35 minutes. Such a circuit can surely save a lot of power.







The circuit is based on quad 2 input CMOS IC 4011 (U1).The resistor R1 and capacitor C1 produces the required long time delay. When pushbutton switch S2 is pressed, capacitor C1 discharges and input of the four NAND gates are pulled to zero. The four shorted outputs of U1 go high and activate the transistor Q1 to drive the relay. The appliance connected via the relay is switched ON. When S2 is released the C1 starts charging and when the voltage at its positive pin becomes equal to ½ the supply voltage the outputs of U1 becomes zero and the transistor is switched OFF. This makes the relay deactivated and the appliance connected via the relay is turned OFF. The timer can be made to stop when required by pressing switch S1.



Notes.

* Assemble the circuit on a good quality PCB or common board.
* The circuit can be powered from a 9V PP3 battery or 12V DC power supply.
* The time delay can be varied by varying the values of C1&R1.
* The push button switch S2 is for starting the timer and S1 for stopping the time.
* The appliance can be connected via contacts N1 & N2 of the relay RL1.
* The IC U1 is 2 input quad NAND gate 4011.

Bedside Lamp Timer

The purpose of this circuit is to power a lamp or other appliance for a given time (30 minutes in this case), and then to turn it off. It is useful when reading at bed by night, turning off the bedside lamp automatically in case the reader falls asleep... After turn-on by P1 pushbutton, the LED illuminates for around 25 minutes, but then it starts to blink for two minutes, stops blinking for two minutes and blinks for another two just before switching the lamp off, thus signaling that the on-time is ending. If the user want to prolong the reading, he/she can earn another half-hour of light by pushing on P1. Turning-off the lamp at user's ease is obtained by pushing on P2






Parts:

R1________1K 1/4W Resistor R2________4K7 1/4W Resistor R3_______10M 1/4W Resistor R4________1M 1/4W Resistor R5_______10K 1/4W Resistor C1_______470µF 25V Electrolytic Capacitor C2-C4____100nF 63V Polyester Capacitors D1-D4____1N4002 100V 1A Diodes D5_______5mm. Red LED IC1______4012 Dual 4 input NAND gate IC IC2______4060 14 stage ripple counter and oscillator IC Q1_______BC328 25V 800mA PNP Transistor Q2_______BC547 45V 100mA NPN Transistor P1,P2____SPST Pushbuttons T1_______220V Primary, 9 + 9V Secondary 1VA Mains transformer RL1______10.5V 470 Ohm Relay with SPDT 2A 220V switch PL1______Male Mains plug SK1______Female Mains socket Q1 and Q2 form an ALL-ON ALL-OFF circuit that in the off state draws no significant current. P1 starts the circuit, the relay is turned on and the two ICs are powered. The lamp is powered by the relay switch, and IC2 is reset with a positive voltage at pin 12. IC2 starts oscillating at a frequency set by R4 and C4. With the values shown, pin 3 goes high after around 30 minutes, turning off the circuit via C3. During the c6 minutes preceding turn-off, the LED does a blinking action by connections of IC1 to pins 1, 2 & 15 of IC2. Blinking frequency is provided by IC2 oscillator at pin 9. The two gates of IC1 are wired in parallel to source more current. If required, a piezo sounder can be connected to pins 1 & 14 of IC1. Obviously, timings can be varied changing C4 and/or R4 values.

Timed Beeper

This circuit is intended for alerting purposes after a certain time is elapsed. It is suitable for table games requiring a fixed time to answer a question, or to move a piece etc. In this view it is a modern substitute for the old sandglass. Useful also for time control when children are brushing teeth (at least two minutes!), or in the kitchen, and so on.







Parts:

R1______220R 1/4W Resistor
R2_______10M 1/4W Resistor
R3________1M 1/4W Resistor
R4_______10K 1/4W Resistor
R5_______47K 1/4W Resistor

C1_______100nF 63V Polyester Capacitor
C2________22µF 25V Electrolytic Capacitor

D1______1N4148 75V 150mA Diode
D2________3mm. Red LED

IC1_____4081 Quad 2 input AND Gate IC
IC2_____4060 14 stage ripple counter and oscillator IC

Q1______BC337 45V 800mA NPN Transistor

P1______SPST Pushbutton (Start)
P2______SPST Pushbutton (Reset)

SW1_____4 ways Switch (See notes)

PS______Piezo sounder (incorporating 3KHz oscillator)

B1______3V Battery (2 AA 1.5V Cells in series)



Pushing on P1 resets IC2 that start oscillating at a frequency fixed by R3 & C1. With values shown, this frequency is around 4Hz. LED D2, driven by IC1A & B, flashing at the same oscillator frequency, will signal proper circuit operation. SW1 selects the appropriate pin of IC2 to adjust timing duration:

* Position 1 = 15 seconds
* Position 2 = 30 seconds
* Position 3 = 1 minute
* Position 4 = 2 minutes

When the selected pin of IC2 goes high, IC1C drives Q1 and the piezo sounder beeps intermittently at the same frequency of the LED. After around 7.5 seconds pin 4 of IC2 goes high and IC1D stops the oscillator through D1. If you want to stop counting in advance, push on P2.
Notes:

* SW1 can be any type of switch with the desired number of ways. If you want a single fixed timing duration, omit the switch and connect pins 9 & 13 of IC1 to the suitable pin of IC2.
* The circuit's reset is not immediate. Pushing P2 forces IC2 to oscillate very fast, but it takes some seconds to terminate the counting, especially if a high timer delay was chosen and the pushbutton is operated when the circuit was just starting. In order to speed the reset, try lowering the value of R5, but pay attention: too low a value can stop oscillation.
* Frequency operation varies with different brand names for IC2. E.g. Motorola's ICs run faster, therefore changing of C1 and/or R3 values may be necessary.
* You can also use pins 1, 2, 3 of IC2 to obtain timings of 8, 16 and 32 minutes respectively.
* An on-off switch is not provided because when off-state the circuit draws no significant current.

Long delay Timer

This timer was designed mainly to switch off a portable radio after some time: in this way, one can fall asleep on the sand or on a hammock, resting assured that the receiver will switch off automatically after some time, saving battery costs.






Parts: R1______________10M 1/4W Resistor R2_______________4K7 1/4W Resistor R3_______________1K 1/4W Resistor (Optional, see Text) C1_____________220µF 25V Electrolytic capacitor D1______________LED any type and color (Optional, see Text) D2___________1N4148 75V 150mA Diode (Optional, see Text) IC1____________4011 Quad 2 Input NAND Gate CMos IC (See Notes) Q1____________BC337 45V 800mA NPN Transistor P1,P2__________SPST Pushbuttons RL1___________Relay with SPDT 2A @ 230V switch (Optional, see Text) Coil Voltage 12V - Coil resistance 200-300 Ohm Circuit operation: R1 and C1 provide a very long time constant. When P2 is momentarily closed, C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the four gates of IC1 wired in parallel. The four paralleled gate outputs of the IC go therefore to the high state and the battery voltage is available at Q1 Emitter. When P2 is released, C1 starts charging slowly through R1 and when the voltage at its positive lead has reached about half the battery voltage, the IC gate outputs fall to zero, stopping Q1. This transistor can directly drive a portable radio receiver or different devices drawing a current up to about 250mA. Connecting a Relay across the Emitter of Q1 and negative ground, devices requiring much higher voltage and current operation can be driven through its contacts. Pushing on P2 for 1 to 5 seconds, the circuit starts and then will switch off after about 35 minutes. This time delay can be varied by changing R1 and/or C1 values. P1 will stop the timer if required. LED D1 is optional and can be useful to signal relay operation when the load is placed far from the timer. Notes: * A 4011 Quad 2 Input NAND Gate was used for IC1, but many other CMos gates or inverter arrays can be used in its place, e.g. 4001, 4002, 4025, 4012, 4023, 4049, 4069. With these devices, all inputs must be tied together and also all outputs, as shown in the Circuit diagram. * The operating voltage of this circuit should lie in the 6 - 12V range.

Time Delay Relay

When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is only limited by what kind of relay you decide to use



Parts:
C1 See Notes
R1 See Notes
D1 1N914 Diode
U1 4011 CMOS NAND Gate IC
K1 6V Relay
S1 Normally Open Push Button Switch
MISC Board, Wire, Socket For U1

5 to 30 Minute Timer

Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type. Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as :-

Timing = 1.1 C1 x R1

Note that R1 has a value of 8.2M with S3 at position "a" and 49.2M at position "f". This equates to just short of 300 seconds for each position of S3. C1 and R1 through R6 may be changed for different timing periods. The output current from Pin 3 of the timer, is amplified by Q1 and used to drive a relay.

Parts
Relay 9 volt coil with c/o contact (1)
S1 On/Off (1)
S2 Start (1)
S3 Range (1)
IC1 7555 (1)
B1 9V (1)
C1 33uF CAP (1)
Q1 BC109C NPN (1)
D1 1N4004 DIODE (1)
C2 100n CAP (1)
R6,R5,R4,R3,R2,R1 8.2M RESISTOR (6)
R8 100k RESISTOR (1)
R7 4.7k RESISTOR (1)